From my point of view it is a very close run between the Blackbird and the Timeless OC. In efficency the Blackbird perhaps scores a little bit better while I would say the Timeless gives you a small amount more confort but all this is really depends on personal choice. But these 2 razors are really different in threir character. I felt the Timeless more intuitive than the Blackbird. With the Blackbird I had (and still have) a learning curve regarding handling, angle, blade choice, etc. while the Timeless was more predictible already during the first shave.
But we should also consider that the Blackbird is an SB razor while we are looking at thr OC Timeless at the moment. It will be interesting to see how the Timeless SB feels in relation to the OC version and to the Blackbird.
Best Regards
Marco